scholarly journals Synthesis of a tyrosinase inhibitor by consecutive ethenolysis and cross-metathesis of crude cashew nutshell liquid

2018 ◽  
Vol 14 ◽  
pp. 2737-2744 ◽  
Author(s):  
Jacqueline Pollini ◽  
Valentina Bragoni ◽  
Lukas J Gooßen
Keyword(s):  
First Generation ◽  
Anacardic Acid ◽  
Side Chain ◽  
Tyrosinase Inhibitor ◽  
Target Compound ◽  
Selective Precipitation ◽  
Acid Component ◽  
Cross Metathesis ◽  
Cashew Nutshell Liquid ◽  
Bond Isomers

A convenient and sustainable three-step synthesis of the tyrosinase inhibitor 2-hydroxy-6-tridecylbenzoic acid was developed that starts directly from the anacardic acid component of natural cashew nutshell liquid (CNSL). Natural CNSL contains 60–70% of anacardic acid as a mixture of several double bond isomers. The anacardic acid component was converted into a uniform starting material by ethenolysis of the entire mixture and subsequent selective precipitation of 6-(ω-nonenyl)salicylic acid from cold pentane. The olefinic side chain of this intermediate was elongated by its cross-metathesis with 1-hexene using a first generation Hoveyda–Grubbs catalyst, which was reused as precatalyst in a subsequent hydrogenation step. Overall, the target compound was obtained in an overall yield of 61% based on the unsaturated anacardic acid content and 34% based on the crude CNSL.

scholarly journals Multiblock Copolymers of Norbornene and Cyclododecene: Chain Structure and Properties

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1756
Author(s):  
Yulia I. Denisova ◽  
Georgiy A. Shandryuk ◽  
Marianna P. Arinina ◽  
Ivan S. Levin ◽  
Vsevolod A. Zhigarev ◽  
...  
Keyword(s):  
First Generation ◽  
Average Length ◽  
Chain Structure ◽  
Random Copolymers ◽  
Multiblock Copolymers ◽  
Structure Property ◽  
Reaction Conditions ◽  
Property Relations ◽  
Cross Metathesis

We investigate the structure–property relations of the multiblock copolymers of norbornene with cyclododecene synthesized via the macromolecular cross-metathesis reaction between amorphous polynorbornene and semicrystalline polydodecenamer in the presence of the first-generation Grubbs catalyst. By adjusting the reaction time, catalyst amount, and composition of the initial system, we obtain a set of statistical multiblock copolymers that differ in the composition and average length of norbornene and dodecenylene unit sequences. Structural, thermal, and mechanical characterization of the copolymers with NMR, XRD, DSC (including thermal fractionation by successive self-nucleation and annealing), and rotational rheology allows us to relate the reaction conditions to the average length of crystallizable unit sequences, thicknesses of corresponding lamellas, and temperatures of their melting. We demonstrate that isolated dodecenylene units can be incorporated into crystalline lamellas so that even nearly random copolymers should retain crystallinity. Weak high-temperature endotherms observed in the multiblock copolymers of norbornene with cyclododecene and other cycloolefins could indicate that the corresponding systems are microphase-separated in the melt state.

scholarly journals Cross metathesis-mediated synthesis of hydroxamic acid derivatives

2018 ◽  
Vol 14 ◽  
pp. 3070-3075 ◽  
Author(s):  
Shital Kumar Chattopadhyay ◽  
Subhankar Ghosh ◽  
Suman Sil
Keyword(s):  
Hydroxamic Acid ◽  
Cyclic Peptide ◽  
Alternative Synthesis ◽  
Acid Component ◽  
Cross Metathesis ◽  
Reaction Proceeds ◽  
Amino Acid Component ◽  
Short Time ◽  
Unusual Amino Acid ◽  
Hydroxamic Acid Derivatives

An alternative synthesis of α,ß-unsaturated hydroxamates via cross metathesis between a class-I olefin and N-benzyloxyacrylamide is reported. The reaction proceeds better in the presence of Grubbs’ second generation catalyst within short time and in good yields (57–85%) with a range of substrates. Subsequent hydrogenation of each of the CM products delivers the title compounds in moderate to very good yield (70–89%). An important demonstration of the protocol is the preparation of the unusual amino acid component of the bioactive cyclic peptide Chap-31.

Side-Chain Modification and “Grafting Onto” via Olefin Cross-Metathesis

2012 ◽  
Vol 33 (23) ◽  
pp. 2023-2028 ◽  
Author(s):  
Lucas Montero de Espinosa ◽  
Kristian Kempe ◽  
Ulrich S. Schubert ◽  
Richard Hoogenboom ◽  
Michael A. R. Meier
Keyword(s):  
Side Chain ◽  
Cross Metathesis ◽  
Grafting Onto

α-Helix mimetics as inhibitors of protein–protein interactions

2008 ◽  
Vol 36 (6) ◽  
pp. 1414-1417 ◽  
Author(s):  
Ishu Saraogi ◽  
Andrew D. Hamilton
Keyword(s):  
Protein Interactions ◽  
First Generation ◽  
Side Chain ◽  
Protein Protein Interactions ◽  
Substitution Pattern ◽  
Pathological Conditions ◽  
Synthetic Accessibility ◽  
Helix Mimetics ◽  
Viable Approach ◽  
Α Helix

The inhibition of protein–protein interactions using small molecules is a viable approach for the treatment of a range of pathological conditions that result from a malfunctioning of these interactions. Our strategy for the design of such agents involves the mimicry of side-chain residues on one face of the α-helix; these residues frequently play a key role in mediating protein–protein interactions. The first-generation terphenyl scaffold, with a 3,2′,2″-substitution pattern, is able to successfully mimic key helix residues and disrupt therapeutically relevant interactions, including the Bcl-XL–Bak and the p53–hDM2 (human double minute 2) interactions that are implicated in cancer. The second- and third-generation scaffolds have resulted in greater synthetic accessibility and more drug-like character in these molecules.

scholarly journals Multivalent polyglycerol supported imidazolidin-4-one organocatalysts for enantioselective Friedel–Crafts alkylations

2015 ◽  
Vol 11 ◽  
pp. 730-738 ◽  
Author(s):  
Tommaso Pecchioli ◽  
Manoj Kumar Muthyala ◽  
Rainer Haag ◽  
Mathias Christmann
Keyword(s):  
Catalytic System ◽  
First Generation ◽  
High Loading ◽  
Turnover Rates ◽  
Selective Precipitation ◽  
Unsaturated Aldehydes ◽  
Cuaac Reaction ◽  
Hyperbranched Polyglycerol

The first immobilization of a MacMillan’s first generation organocatalyst onto dendritic support is described. A modified tyrosine-based imidazolidin-4-one was grafted to a soluble high-loading hyperbranched polyglycerol via a copper-catalyzed alkyne–azide cycloaddition (CuAAC) reaction and readily purified by dialysis. The efficiency of differently functionalized multivalent organocatalysts 4a–c was tested in the asymmetric Friedel–Crafts alkylation of N-methylpyrrole with α,β-unsaturated aldehydes. A variety of substituted enals was investigated to explore the activity of the catalytic system which was also compared with monovalent analogues. The catalyst 4b showed excellent turnover rates and no loss of activity due to immobilization, albeit moderate enantioselectivities were observed. Moreover, easy recovery by selective precipitation allowed the reuse of the catalyst for three cycles.

Side-Chain Truncation of Apicularen A by Olefin Cross-Metathesis with Ethylene

2007 ◽  
Vol 70 (8) ◽  
pp. 1377-1379 ◽  
Author(s):  
Larissa Jundt ◽  
Gerhard Höfle
Keyword(s):  
Side Chain ◽  
Cross Metathesis ◽  
Apicularen A

scholarly journals 4-[(E)-4-Hydroxybut-2-en-1-yl]-2-methoxyphenol

IUCrData ◽  
2016 ◽  
Vol 1 (6) ◽  
Author(s):  
Kyle S. Knight ◽  
Michael C. Orick
Keyword(s):  
Hydrogen Bonds ◽  
Aromatic Ring ◽  
Dihedral Angle ◽  
Title Compound ◽  
Side Chain ◽  
Metathesis Reaction ◽  
Cross Metathesis ◽  
Compound C

The title compound, C11H14O3, was synthesized by a cross-metathesis reaction. The dihedral angle between the aromatic ring and the butenol side chain is 30.2 (2)°. In the crystal, inversion dimers are formed through O—H...O hydrogen bonds and these are linked into chains by additional O—H...O contacts. These chains are linked into sheets in thebcplane by C—H...O hydrogen bonds.

scholarly journals Synthesis and Glycosidase Inhibition of Broussonetine M and Its Analogues

Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3712 ◽  
Author(s):  
Wu ◽  
Kinami ◽  
Kato ◽  
Li ◽  
Fleet ◽  
...  
Keyword(s):  
Natural Product ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Alkyl Side Chain ◽  
Asymmetric Allylation ◽  
Pyrrolidine Ring ◽  
Cross Metathesis ◽  
Similar Strategy ◽  
Key Steps ◽  
Glycosidase Inhibition

Cross-metathesis (CM) and Keck asymmetric allylation, which allows access to defined stereochemistry of a remote side chain hydroxyl group, are the key steps in a versatile synthesis of broussonetine M (3) from the d-arabinose-derived cyclic nitrone 14. By a similar strategy, ent-broussonetine M (ent-3) and six other stereoisomers have been synthesized, respectively, starting from l-arabino-nitrone (ent-14), l-lyxo-nitrone (ent-3-epi-14), and l-xylo-nitrone (2-epi-14) in five steps, in 26%–31% overall yield. The natural product broussonetine M (3) and 10’-epi-3 were potent inhibitors of β-glucosidase (IC50 = 6.3 μM and 0.8 μM, respectively) and β-galactosidase (IC50 = 2.3 μM and 0.2 μM, respectively); while their enantiomers, ent-3 and ent-10’-epi-3, were selective and potent inhibitors of rice α-glucosidase (IC50 = 1.2 μM and 1.3 μM, respectively) and rat intestinal maltase (IC50 = 0.29 μM and 18 μM, respectively). Both the configuration of the polyhydroxylated pyrrolidine ring and C-10’ hydroxyl on the alkyl side chain affect the specificity and potency of glycosidase inhibition.

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